Diabetes, or diabetes mellitus, disease characterized by the absence or inadequate secretion of insulin. Normally, sugars and starches (carbohydrates) in food are processed by digestive juices into a form of sugar called glucose, or blood sugar, which is the fuel used by the body. Insulin, a hormone produced by the pancreas, is a major regulator of this process. In the diabetic individual, either the body does not produce enough insulin, or the available insulin is somehow blocked or inactivated by other substances and is prevented from performing its primary function. Because of this impairment, excessive amounts of glucose accumulate in the blood and tissues and overflow into the urine. In juvenile-onset diabetes, there is a total or substantial lack of insulin, and daily injections of the hormone are necessary for survival. Juvenile-onset diabetes usually begins in the early years, from infancy to young adulthood. In adult-onset diabetes, which accounts for 85–90% of all cases, most individuals do not require insulin treatment and can maintain their blood sugar at relatively normal levels by controlling their weight and adhering to a prescribed diet. In general, women are more susceptible to this type than men, and the disease tends to occur most frequently in certain “high-risk” groups: close relatives of individuals who have diabetes, people who are overweight or over 40, and women who have given birth to large infants.
The early symptoms of diabetes stem from the increased amount of sugar in the blood and urine. Since the kidneys excrete excessive amounts of water along with the excess sugar, uncontrolled diabetics are likely to urinate frequently and to be constantly thirsty. Because the sugar in the blood is not being converted to energy, they will be weak, tired, and hungry. Because of the calories lost in the urine, they will lose weight, no matter how much they eat. Treatment may include diet, exercise, and insulin. Diabetics must generally cut down on sugar and sugar-rich foods, and on fats found in fatty meats, most cheese, butter, margarine, and nuts. Regular exercise increases the ability of the body to use food. All juvenile-onset and a few adult-onset diabetics must take insulin in order to use blood sugar in a comparatively normal manner.
“Hypo” attacks, due to hypoglycemia (too little sugar in the blood), may result when the diet-exercise-insulin balance is disrupted. Symptoms include tremor, hunger, sweating, headache, nausea, blurred vision, and eventually, if not promptly treated, loss of consciousness (diabetic coma). Prompt relief can usually be obtained by taking sugar in water.
Hyperglycemia (too much sugar in the blood) can occur when a diabetic fails to take sufficient insulin or to follow a meal plan; other contributory causes can be infection and illness. In this condition, fat is burned to supply energy, producing an increasingly acid condition of the blood and other body fluids (acidosis) due to the accumulation of so-called ketone substances, including acetone. Usual symptoms are nausea, drowsiness, extreme thirst, headache, blurred vision, abdominal pains, and rapid breathing. Acetone and high blood sugar levels can be detected in routine urine tests. As diabetics are more susceptible to infections than other individuals, even minor wounds should receive careful attention. Serious infections are frequently a precipitating factor in acidosis and diabetic coma. Despite satisfactory control of blood sugar levels through diet and the administration of insulin, in many cases long-term complications of diabetes develop, primarily those affecting blood vessels, nerves, kidneys, and eyes. In general, the juvenile diabetics are more severely affected.